Match List I with List II List I List II A. Nylon 6,6 I. Elastomer B.…

The correct answer is Option (4) → A-III, B-IV, C-II, D-I

Polymers are classified by their molecular forces:

• (A) Nylon 6,6 — a polyamide; strong hydrogen bonding between chains gives high tensile strength and crystallinity, so it is a fibre → III.

• (B) Bakelite — a phenol–formaldehyde polymer that becomes heavily cross-linked on heating and cannot be re-melted, so it is thermosetting → IV.

• (C) Polystyrene — linear chains with intermediate forces; it softens on heating and hardens on cooling repeatedly, so it is a thermoplastic → II.

• (D) Buna-S — a copolymer of 1,3-butadiene and styrene with weak forces and a few cross-links; it can be stretched and regains its shape, so it is an elastomer → I.

Note 1: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.

NCERT (Pre-rationalised edition, 2022-23):
Classification Based on Molecular Forces – “… 1. Elastomers: These are rubber-like solids with elastic properties. In these elastomeric polymers, the polymer chains are held together by the weakest intermolecular forces. … The examples are buna-S, buna-N, neoprene, etc.
2. Fibres: Fibres are the thread forming solids which possess high tensile strength and high modulus. … The examples are polyamides (nylon 6, 6), polyesters (terylene), etc.
3. Thermoplastic polymers: These are the linear or slightly branched long chain molecules capable of repeatedly softening on heating and hardening on cooling. … Some common thermoplastics are polythene, polystyrene, polyvinyls, etc.
4. Thermosetting polymers: These polymers are cross linked or heavily branched molecules, which on heating undergo extensive cross linking in moulds and again become infusible. … Some common examples are bakelite, urea-formaldehyde resins, etc.”

Note 2: The same/similar question has been asked in different years by NTA as per the details given below: